An experimentally simple, mild and straightforward synthetic route towards diversely functionalized (E)-3-acylacrylic acids is described, with Horner–Wadsworth–Emmons (HWE) reaction as the key step. The substrate scope and limitations of the HWE reaction were investigated with a range of β-ketophosphonates. Glyoxylic acid monohydrate was demonstrated to be fully compatible with the HWE reaction conditions